html {
  background-color: gray;
  padding: 5mm 2mm 2mm 2mm;
  text-align: center;
}
body {
  background-color: white;
  margin: auto auto auto auto;
  padding: 1mm 1mm 1mm 2.5mm;
  border: solid black thin;
  max-width: 120ex;
  text-align: left;
}
h1, h2, h3, h4, h5, h6 {
  font-familly: sans-serif;
}
h1 {
  margin-top: 1mm;
}
.nav {
  float: right;
}